BOSTON — Bitter cold kept its grip on the Northeast on Saturday, while warmer temperatures brought relief to the Midwest and Southeast.

A day after schools in a dozen states closed and Alabama was colder than Alaska, temperatures in the South climbed into the 40s, thawing water fountains and pipes. Parts of the Northeast, however, persisted with temperatures barely in the teens.

In Boston, the Pine Street Inn shelter sent vans to look for the homeless during the day, rather than just at night, said shelter spokeswoman Barbara Trevisan. The shelter also expanded its hours and is serving an extra meal.

Trevisan said the shelter, which holds about 700 people, has been packed in recent nights. Boston’s low early Saturday was eight degrees, and temperatures hovered near zero elsewhere in the state.

The weather led to at least seven deaths. In northeast Ohio, authorities said an 8-year-old boy drowned Friday after he fell into a partially frozen creek and got stuck under the ice. Temperatures had reached several degrees below zero in the town of Mentor, Ohio.

Near Pittsburgh, the frozen body of a man was found outside his home at midday Friday. The cause of death was not immediately determined.

Subzero temperatures of 30 below zero in Berlin, N.H., forced firefighters from at least four communities to battle a blaze in shifts Saturday morning. At least two buildings were destroyed.

In downtown Columbus, Ohio, firefighters put out a fire that burned for several hours and destroyed a block of buildings.